The present invention relates to a method for growing epitaxial layers of III-V compound semiconductors, and more particularly, to a method for growing epitaxial layers of III-V compound semiconductors of new binary, ternary and quaternary alloys having the characteristics of low temperature growth, good stability and high-purity, using remote plasma.
Recently, the developing communication industry has urgently required electronic devices of ultrahigh speed and ultrahigh frequency, together with optical devices for long wavelength between 1.3 .mu.m and 1.55 .mu.m including ultra low loss wavelength of optical fibers.
It is well known that the above requirements can be satisfied with the devices composed of (Ga, In, Al)--(As, P, Sb) based on binary, ternary and quaternary III-V compound semiconductor alloys.
In manufacturing the compound semiconductors, various methods such as liquid phase epitaxy(LPE), vapor phase epitaxy(VPE), molecular beam epitaxy(MBE) and metalorganic chemical vapor deposition(MOCVD) are utilized. Among them, MBE and MOCVD methods are generally suitable for the above requirements. According to the MBE methods, solid sources are heated under the ultrahigh vacuum condition of 10.sup.-10 torr or below. And, the vaporized sources are deposited on a heated substrate to a low temperature of 500.about.600.degree. C. The low temperature process can enable the deposition of fine atomic layers and molecular layers to be controlled easily. But, the growth rate of a desired layer is very slow and a plurality of wafers can not be processed simultaneously in a batch. Further, MBE method is disadvantageous economically because the method should be performed under ultrahigh vacuum conditions which require costly facilities.
MOCVD method has more advantages for a desired epitaxial layer to be rapidly grown and a plurality of wafers to be processed simultaneously in a batch. Further, MOCVD method is more economical. But, the group V source gases used in this method such as AsH.sub.3 and PH.sub.3, are fatally poisonous, thus careful attention should be given to the handling thereof.
Further still, MOCVD method requires a relatively high growth temperature in the range of 650.about.1000.degree. C. depending on the sorts of materials. Thus, when the multilayer heterostructures comprising a plurality of fine layers are formed, atoms of each layer may be diffused mutually between each layer and the control of the diffusion range of the atoms in each layer is difficult.